/*
 * Copyright (c) 2018, vindell (https://github.com/vindell).
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package okhttp3.spring.boot.ext;

import java.io.IOException;

import com.google.common.net.HttpHeaders;

import okhttp3.Interceptor;
import okhttp3.MediaType;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;
import okio.BufferedSink;
import okio.GzipSink;
import okio.Okio;

/**
 * This interceptor compresses the HTTP request body. Many webservers can't
 * handle this!
 */
public class GzipRequestInterceptor implements Interceptor {

	@Override
	public Response intercept(Interceptor.Chain chain) throws IOException {

		Request originalRequest = chain.request();
		if (originalRequest.body() == null || originalRequest.header(HttpHeaders.CONTENT_ENCODING) != null) {
			return chain.proceed(originalRequest);
		}

		Request compressedRequest = originalRequest.newBuilder().header(HttpHeaders.CONTENT_ENCODING, "gzip")
				.method(originalRequest.method(), gzip(originalRequest.body())).build();
		return chain.proceed(compressedRequest);
	}

	private RequestBody gzip(final RequestBody body) {
		
		return new RequestBody() {
			
			@Override
			public MediaType contentType() {
				return body.contentType();
			}

			@Override
			public long contentLength() {
				return -1; // We don't know the compressed length in advance!
			}

			@Override
			public void writeTo(BufferedSink sink) throws IOException {
				BufferedSink gzipSink = Okio.buffer(new GzipSink(sink));
				body.writeTo(gzipSink);
				gzipSink.close();
			}
			
		};
	}
}